Evidence suggests a significant percentage of adolescent daily smokers are interested in trying to quit smoking, frequently make attempts to quit, yet are unsuccessful in maintaining abstinence. Current models of relapse devote scant attention to mechanisms involved in adolescent smoking cessation despite widespread acceptance that adolescent daily smokers are more likely to be adult smokers. A promising new theory of early lapse from the adult smoking literature is distress tolerance. According to this theory, how one responds to discomfort is more important than severity of discomfort itself. Instead of focusing on severity of affective and physical symptoms occurring in the cessation process, examining factors surrounding how one reacts to these symptoms may be more promising. The objective of this proposal is to support the candidate's development of skills to perform patient-oriented research in the area of adolescent smoking cessation. The career development plan consists of obtaining training in biobehavioral and affective factors in adolescent smoking, relapse phenomena, and basic research. The University of Maryland College Park is an intellectually stimulating environment with superb resources for the candidate's successful achievement of her training goals. Dr. Carl Lejuez, the primary mentor, and Drs. Brown, Mermelstein, Dahl, and Strong (co mentors) are each experts in experimental psychopathology, smoking relapse, adolescent smoking, adolescent affect regulation, and statistics, respectively. The primary research aim is to examine the influence of pre-quit emotional and behavioral variables on lapse and relapse to smoking among 60 adolescent daily smokers undergoing a quit attempt. Participants will complete assessments of tobacco and other substance use, depressive symptoms, mood, anxiety sensitivity, personality, and nicotine dependence; and four laboratory challenge procedures: (a) mental arithmetic, (b) mirror tracing, (c) breath-holding, and (d) the cold pressortask. Beginning at baseline, quit day, and at days 7,14, 21, and 28, participants will be assessed for tobacco use, mood, and withdrawal symptoms. We will examine effects of behavioral reactivity to the challenge procedures on survival to first cigarette lapse and relapse. It is expected the results of this K23 project will increase basic knowledge about the role of vulnerability factors in adolescent smoking lapse and relapse, and will have direct implications for novel distress tolerance treatments for adolescent smoking. [unreadable] [unreadable] [unreadable]